Due to the developments in the micro machining technology, a micro flow controller module comprising a plurality of sensors, actuators and control circuits may be integrated in one single dice. An integrated micro flow controller prepared with the micro machining technology is capable of measuring and controlling flows within a microchannel. When the flow to be measured and controlled is a gaseous flow, the applicable velocity may be under 1/min. For a liquid flow, the applicable velocity may be at the scale of .mu.1/min. The geometric scale of a flow controller is centimeter. The advantages of the integrated micro flow controller include energy saving, short response time and compactness. Micro flow controllers may further be associated in matrix to precisely control flows in a larger scale.
A micro flow controller module generally includes a flow sensor to measure the velocity of a flow, a microvalve to control the velocity and a system controller circuit to control the operation of the microvalve. In the conventional art, the microvalve may be an electromagnetic or a piezoelectric valve. The flow sensor may be a wicked thermal flow sensor. Due to the numbers and volumes of the components, volume of a micro flow controller is always bulky. In addition, these components must be prepared and assembled under superfine processes and packaged mechanically. As a result, manufacture costs of the micro flow controller may not be reduced.
It is thus a need in the industry to have an integrated flow controller where a flow sensor and a microvalve are integrated in one single dice. It is also a need to have a compact flow controller module that may be prepared under the semiconductor manufacture process.